Such magnetic control devices are already known to the person skilled in the art. The patent document U.S. Pat. No. 4,038,814 describes in particular several embodiments of such a device. In particular, the embodiment described with reference to FIGS. 6 and 7 relates to a wristwatch of a generally rectangular exterior form, and one of the sides of which carries a guide rail. A plastic cursor containing a magnet is provided in order to slide along this rail. A non-specified number of reed contacts are disposed inside the watch facing the guide rail. By making the magnet slide, the wearer of the watch can selectively close one or other of the reed contacts and thus can control the watch. This control device functions therefore without mechanical or electrical connection between the outside and the inside of the watch.
This device of prior art has certain defects. First of all it is not unobtrusive since the guide rail extends practically over the entire length of one of the sides of the watch. Furthermore it does not appear that it is possible to reduce greatly the size of this prior art device. In fact the described configuration makes it necessary to dispose all the reed contacts side by side in one line. However, the width of the smallest reed contacts known approaches a millimeter. Furthermore, the magnetic field must be intense enough to act through the thickness of the middle part of the watch. In these conditions it is necessary to space the contacts sufficiently apart in order that two contacts are not closed at the same time.
One object of the present invention is therefore to provide a control device which functions without a mechanical or electrical connection between the outside and the inside of the timepiece and which is more compact than those of prior art.
Another object of the present invention is to provide a control device within which the amplitude of the translational movement which the control member must perform is greatly reduced.
Another object is to provide a magnetic control device which can have the exterior appearance of a traditional mechanical control device.
Yet another object of the present invention is to provide a magnetic control device, the control member of which can be adapted easily in order to be actuated equally in rotation, in the manner of a traditional control stem.